Low temperature bonding methods can enable technology by allowing the manufacture of devices that include a broader range of materials. Temperature processing can limit materials selection due to decomposition, vaporization, dissolution, or coefficient of expansion. For example, a variety of micro devices for chemical and biochemical analysis are being developed.
The fabrication of many of these devices requires the bonding of glass components, such as the bonding of a glass cover plate to a photo lithographically etched glass substrate, in order to produce a device containing closed micro channels. This bonding process has previously been carried out by fusing the two components at high temperature (e.g. 500-1,100.degree. C.), preventing the inclusion of bio-molecules or other temperature-sensitive materials in open channels. It also allows the two components to have different thermal coefficients of expansion.
Currently under development are devices for the analysis of nucleic acids. These devices require the attachment of nucleic acid probes to specific sites within the micro channels formed in a glass substrate, which is most efficiently carried out in open channels prior to bonding a cover plate to the substrate. However, conventional, high temperature bonding techniques would damage the probes and thus compromise the integrity of the analysis. Moreover, adhesive bonding techniques are undesirable given the very small (micron order) dimensions of the micro channels.
Thus, a continuing need exists for a low temperature bonding technique.